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Figure 3 | BMC Microbiology

Figure 3

From: The Pseudomonas putida Lon protease is involved in N-acyl homoserine lactone quorum sensing regulation

Figure 3

Gene promoter activities of ppuI and rsaL in P. putida WCS358 and lon mutant derivatives. A. Promoter activities of the ppuI C12-3-oxo-AHL synthase in P. putida WCS358 (pPPUI220), in the lon protease mutant derivative P. putida IBE4 (pPPUI220) and lon mutant containing a plasmid expressing the Lon protease, P. putida IBE4 (pPPUI220)(pBBRlon). The ppuI promoter activities are expressed in β-galactosidase activity (Miller Units) as the plasmid construct pPPUI220 contains the ppuI promoter transcriptionally fused to a promoterless lacZ gene (see text for all details). Standard deviation bars are given on the mean value of three independent experiments. Logarithmic phase (Log.) corresponds to 8 hours of growth, stationary phase (Stat.) to 16 hrs and late stationary (Late stat.) to 48 hours of growth. Statistical analysis was performed with Anova resulting in a significant main effect of the mutation with F(1,14) = 18.90 and p < .001. Statistical analysis including the age of the cultures results in a significant difference between the wild type and the IBE4 mutant in the Logarithmic phase of growth [F(1,14) = 28.70 p < .001]. B. Promoter activities of the rsaL in P. putida WCS358 (pRSA220), in the lon protease mutant derivative P. putida IBE4 (pRSA220) and lon mutant containing a plasmid expressing the Lon protease, P. putida IBE4 (pRSA220)(pBBRlon). The ppuI promoter activities are expressed in β-galactosidase activity (Miller Units) as the plasmid construct pRSA220 contains the rsaL promoter transcriptionally fused to a promoterless lacZ gene. Standard deviation bars are given on the mean value of three independent experiments. Logarithmic phase (Log.) corresponds to 8 hours of growth, stationary phase (Stat.) to 16 hrs and late stationary (Late stat.) to 48 hours of growth. Statistical analysis was performed with Anova resulting in a significant main effect of the mutation with F(1,18) = 126.12 and p < .000001. Statistical analysis including the age of the cultures results in a significant difference between the wild type and the IBE4 mutant in the late stationary phase of growth [F(1,18) = 18.79 p < .001].

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